FR2971144A1 - GLENOIDAL IMPLANT FOR SHOULDER PROSTHESIS AND SURGICAL KIT - Google Patents

Abstract

This glenoid implant (1) for shoulder prosthesis, intended to be implanted in the glenoid of a scapula, comprising an articular body (2), for articulation with the humerus, and a central fixing element (3) of the articular body (2) in the glenoid. The articular body (2) comprises a plate (21), one face (23), intended to be turned towards the glenoid, is provided with a central pin (24) for assembling the articular body (2) with the element central (3). The central element (3) is provided with assembly means with the central pin (24). The glenoid implant (1) comprises means (26, 4) for blocking the rotation of the central element (3) and / or the articular body (2) with respect to the glenoid.

Description

The present invention relates to a glenoid implant for a shoulder prosthesis, and to a surgical kit comprising such a glenoid implant. BACKGROUND OF THE INVENTION Typically, a shoulder prosthesis comprises a glenoid implant, intended to replace the glenoid cavity of the scapula, and / or a humeral implant, intended to replace the head of the humerus. The glenoid implant is generally composed of an articular body, intended to articulate with the head of the humerus, and fixing means for securing the articular body with the scapula. The articular body may be metallic, for example of titanium alloy, ceramic, or synthetic, for example polyethylene. The synthetic materials are slightly deformable, while the metal alloys and ceramics conventionally used are relatively rigid. Therefore, the fixing means must be adapted to the material of the articular body. One of the aims of the invention is to propose fastening means suitable both for metallic and synthetic joint bodies, in order to minimize the number of parts that the surgeon must have in stock. In addition, mixed attachment means reduce the costs of design and manufacture of glenoid implants, since the same attachment means is adapted to several types of joint bodies. Another object of the invention is to reduce the amount of bone tissue that the surgeon must remove from the glenoid cavity to fix the glenoid implant. In a conventional manner, minimally invasive implants are preferred because they make it possible to increase the life of the shoulder prosthesis. In this context, US-A-2007/0219637 proposes a glenoid implant whose attachment to the scapula is made by means of a central stud which is screwed, prior to the installation of the implant, in a socket overmolded at the of the back side of an articular body of the glenoid implant. The locking in rotation of the implant relative to the scapula is provided exclusively by a lateral stud of the body of the implant, which is not quite satisfactory since it involves digging the bone tissue to accommodate the stud Lateral, to the detriment of the respect of the bone constitution of the glenoid. In addition, this implant is relatively complex design since it requires overmolding the socket. US-A-2007/0055380 relates to a glenoid implant which comprises a joint body equipped with several lateral fixing pins, which have a certain elasticity. During the operation, the surgeon implants anchors in the glenoid. The fixing pins are adapted to snap on the anchoring elements.

2 Thus, this method of attachment is not suitable for metal articular bodies, since the fixing pins of the articular body must deform slightly to be fixed to the anchoring elements. In addition, several fixing pins are necessary to block the rotation of the articular body relative to the glenoid, which involves digging in the glenoid several housings to receive several anchoring elements. US-B-6406495 relates to a glenoid implant which comprises an articular body provided with a plurality of lateral fixation pins, intended to be received in holes that the surgeon pierces beforehand into the glenoid. The fixing pins are threaded, and are intended to receive a threaded sleeve, provided externally with longitudinal ribs. During the operation, the surgeon first screws the sleeves on the fixing pins, then it impacts the assembly in the glenoid. Here again, several fixation pins are necessary to block the rotation of the articular body with respect to the glenoid, which deteriorates the bone tissue of the glenoid and contributes to reducing the life of the implant.

FR-A-2579454 proposes a glenoid implant composed of an articular body attached to the glenoid by means of a threaded metal sleeve, which is screwed into the glenoid and which defines a frustoconical housing. The articular body is provided with a frustoconical pin that the surgeon fits into the frustoconical housing of the metal sleeve. However, the sleeve does not block the rotation of the articular body relative to the scapula as it tends to unscrew the glenoid. To block the rotation of the glenoid implant, the articular body is assembled to the scapula by means of two lateral attachment tabs, screwed on either side of the scapula, this makes this implant relatively invasive, and complicates the implant placement. US-A-2007/0260321 discloses a fastener for securing an articular body in the glenoid. The fastening element is in the form of a hollow frustoconical sleeve, provided externally with longitudinal ribs or barbs (designated by the term "barbs" in the text). The ribs or barbs serve to block the fixation element in the glenoid. A fastening screw is passed through the fastener and allows it to be immobilized more effectively. The fastening element is traversed by a frustoconical longitudinal opening, in which are formed two longitudinal grooves. The articular body is provided with a frustoconical pin equipped with longitudinal ribs and is fitted into the frustoconical opening of the fastening element, positioning the ribs in the grooves to block the rotation of the articular body relative to the element of fixation. However, this fastening element is not adapted to receive a synthetic joint body, because a fitting cone fixing is not effective to retain a synthetic joint body in the fastener. In order to overcome the drawbacks mentioned above, the subject of the invention is a glenoid implant for a shoulder prosthesis intended to be implanted in the glenoid of a scapula, comprising an articular body, for articulation with the shoulder. humerus, and a central element of fixation of the articular body in the glenus. The articular body comprises a plate whose one face, intended to be turned towards the glenoid, is provided with a central pin assembly of the articular body with the central element. The central element is provided with assembly means with the central pin. The glenoid implant comprises means for blocking the rotation of the central element and / or the articular body relative to the glenoid. Thanks to the invention, the rotational locking of the glenoid implant relative to the scapula is ensured without the surgeon having to dig an additional lateral hole in the glenoid, intended in particular to receive a lateral block of the articular body. In addition, the central element is adapted to receive indifferently a synthetic joint body or a metal or ceramic joint body. According to advantageous but non-obligatory aspects of the invention, such a glenoid implant may incorporate one or more of the following characteristics, taken in any technically permissible combination: the means for locking the rotation comprise a screw, the central element is crossed; longitudinally through a passage opening of the screw, and the shank of the screw is threaded in a direction opposite to a thread carried by the outer lateral surface of the central element. The head of the screw is threaded in the same direction as the screw shank. - The pitch of the thread of the head of the screw is equal to the pitch of the thread of the rod of the screw. - The rotational locking means comprise an outer lateral surface of the central pin of polygonal cross section. The assembly means are adapted to cooperate indifferently with a metal or ceramic joint body and with a synthetic joint body. - The assembly means comprise a frustoconical portion or a frustoconical housing, adapted to cooperate by fitting, including Morse taper type with, respectively, a frustoconical housing or a frustoconical portion of the central pin. - The assembly means comprise a peripheral fin or a peripheral groove adapted to cooperate by flexible deformation and complementarity of shapes, with, respectively, a groove or a fin of the central pin. The plate is of elongate shape and the central pin is offset along a longitudinal axis of the plate, relative to the center of the plate. The invention also relates to a surgical kit, comprising at least one central element, at least one metal or ceramic articular body and at least one synthetic articular body, belonging to a glenoid implant according to the invention. The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings, in which: FIG. 1 is a perspective view of a glenoid implant conforming to FIG. invention; Figure 2 is an axial section of the glenoid implant of Figure 1; Figure 3 is an axial section of a central element of the glenoid implant of Figure 1; FIG. 4 is a side view of a joint body of the glenoid implant of FIG. 1; FIG. 5 is a perspective view of a glenoid implant according to a second embodiment of the invention; Figure 6 is an axial section of the glenoid implant of Figure 5; Figure 7 is an axial section of a central element of the glenoid implant of Figure 5; FIG. 8 is a perspective view of an articular body of the glenoid implant of FIG. 5; FIG. 9 is an exploded perspective view of a glenoid implant according to a third embodiment of the invention; FIG. 10 is an axial perspective section of the glenoid implant of FIG. 9; Figure 11 is an exploded perspective view of a glenoid implant according to a fourth embodiment of the invention; Figure 12 is an axial perspective section of the glenoid implant of Figure 11; Fig. 13 is a view similar to Fig. 10 showing the glenoid implant of Fig. 9 superimposed with a joint body of the glenoid implant of Fig. 11; FIG. 14 is an axial section of the glenoid implant of FIG. 9 superimposed with the articular body of the glenoid implant of FIG. 11; FIG. 15 is an exploded perspective view of a glenoid implant according to a fifth embodiment of the invention; FIG. 16 is an axial section, in perspective, of the glenoid implant of FIG. 15; FIG. 17 is a perspective view of a glenoid implant according to a sixth embodiment of the invention; and Fig. 18 is an axial section of the glenoid implant of Fig. 17.

Figures 1 to 4 show a glenoid implant 1 said anatomical or non-inverted, intended to be implanted in the glenoid of the scapula, not shown, of a human being. The glenoid implant 1 is composed of an articular body 2, a central element 3 for anchoring the articular body 2 in the glene of the scapula, and a screw 4 for locking the element in rotation. central 3 with respect to the scapula. The articular body 2, after being implanted in the glenoid, is adapted to articulate with a head, possibly prosthesis, of the humerus, not shown, of the operated patient, in order to reproduce joint behavior as close as possible to the original behavior of the patient's shoulder. In the following, the qualifiers "superior" and "lower" refer to the orientation of the glenoid implant 1 in FIG. 1, where the articular body 2 is at the top of a longitudinal geometric axis X1-X'1 of the implant 1, while the screw 4 is at the bottom of the axis X1-X'1. The articular body 2, visible more particularly in FIG. 4, comprises a plate 21 generally perpendicular to a longitudinal geometric axis X 2 -X '2 of the articular body 2. The plate 21 delimits a concave upper face 22, which constitutes an articular surface for the shoulder blade joint with the head of the humerus, and a lower face 23, equipped with a central pin 24, which extends along the axis X2-X'2. The central pin 24 comprises a cylindrical upper section 24.1 with circular section, a cylindrical intermediate portion 24.2 with a circular cross-section, of smaller diameter than the upper part, and a frustoconical lower portion 24.3 whose diameter decreases as it moves away from the plate 21. The intermediate portion 24.2 is provided with five fins 25 perpendicular to the axis X2-X'2 and parallel to each other, which are distributed along the central portion 24.2 and which each extend on the periphery of the intermediate portion 24.2.

The articular body 2 consists of one or two synthetic materials, such as polyethylene, PEEK or polyurethane, which gives the fins 25 an elasticity allowing them to deform slightly. The lower face 23 is also equipped with a lateral stud 26 parallel to the axis X2-X'2. The lateral stud 26 comprises an upper portion 26.1 which is connected to the lower face 23 of the plate 21 and a lower portion 26.2 connected to the upper portion 26.1. The upper portion 26.1 is cylindrical with a circular section, and its diameter is smaller than the diameter of the central pin 24. The lower portion 26.2 is frustoconical, and its diameter increases away from the plate 21.

The central element 3, visible more particularly in FIG. 3, is generally in the form of a hollow cylinder with a circular cross section, of longitudinal geometric axis X3-X'3. The central element 3 is delimited by an external lateral surface 31 which carries a self-tapping thread, and is traversed longitudinally by an opening 32, centered on the longitudinal axis X3-X'3, which extends between an upper end 33 and a lower end 34 of the central element 3. The lower end 34 of the central element 3 is frustoconical and its diameter decreases closer to the lower end 34. The opening 32 comprises a cylindrical upper portion 32.1 with circular section, a threaded portion 32.2, of diameter similar to the upper part, a tool-engaging portion 32.3, of hexagonal cross-section, and a cylindrical lower section 32.4 with circular section, threaded and of smaller diameter than the part higher 32.1. The central element 3 is made from a metal alloy or biocompatible ceramic and its rigidity is greater than that of the articular body 2. For example, the central element 3 can be made from stainless steel, titanium or titanium alloy, a cobalt-chromium alloy or PEEK. The central element 3 is not intended to, in use, deform. The screw 4, of longitudinal geometric axis X4-X'4, comprises a head 41 and a threaded self-tapping rod 44. A blind hole 42 with hexagonal section, centered on the axis X4-X'4, is formed in the head 41 of the screw 4. An external lateral surface 43 of the head 41 is threaded, and is extended upwards by a flange 45 of larger diameter than the threaded portion. The screw 4 is made from a metal material or biocompatible ceramic, such as stainless steel, titanium, a titanium alloy or a cobalt-chromium alloy.

It is said that a thread or tapping is "right" when the screwing is done counterclockwise, and that a thread or tapping is "left" when the screwing is done clockwise. The threading of the outer lateral surface 31 of the central element 3 is on the right, as represented by the arrow F3. The threading of the rod 44 of the screw 4 is on the left, as represented by the arrow F44, and the threading of the head 41 of the screw 4 and the tapping of the lower part 32.4 of the opening 32 are on the left, as represented by the arrow F41. When it is advisable to carry out the placing of the glenoid implant 1 in the glenoid of the scapula, the surgeon first pierces a hole in the glenoid, slightly smaller in diameter than the external diameter of the central element 3. Then, the surgeon screws the central element 3 into the glenoid, by means of a tool, not shown, equipped with a hexagonal tip that it inserts into the tool-engaging portion 32.3 of the opening 32. self-tapping thread of the central element 3 allows it to enter the glenoid, specifically in the hole previously made by the surgeon, by tapping. The central element 3 alone allows to fix the articular body 2 in the glenoid. Then, the surgeon makes a hole in the glenoid, slightly smaller in diameter than the diameter of the stem 44 of the screw 4, by passing the wick of a surgical motor through the opening 32 of the central element 3. The wick is guided by a tool, not shown, engaged in one of the parts of the opening 32 and protecting the thread 32.4. The surgeon then screws the head 41 of the screw 4 into this hole, with the aid of a tool, not shown, equipped with a hexagonal end piece which it inserts into the blind hole 42 of the screw 4. The threading of the head 41 of the screw 4 cooperates with the tapping of the lower part 32.4 of the opening 32. The axis X3-X'3 of the central element 3 is then coincident with the axis X4-X'4 The thread of the head 41 of the screw 4 is in the same direction as the thread of the rod 44 of the screw 4, which allows the surgeon, in the same movement, to screw head 41 in the lower 32.4 of the opening 32 and screw the rod 44 into the hole he has just punched in the glenoid. The self-tapping thread of the rod 44 of the screw 4 improves the anchoring of the screw 4 in the glenoid. At the end of the stroke, the collar 45 of the head 41 of the screw 4, which is larger in diameter than the lower part 32.4 of the opening 32, makes it possible to retain the head 41 of the screw 4 in the opening 32 preventing it from passing through the opening 32. Advantageously but not mandatory, the threading of the head 41 of the screw 4 comprises two threads, to facilitate the setting of this thread in the tapping of the lower part 32.4 of the In addition, advantageously but not obligatory, the pitch of the thread of the head 41 of the screw 4 is equal to the pitch of the thread of the rod 44 of the screw 4, to optimize the penetration of the screw 4 in FIG. the glenoid when the thread of the head 41 of the screw 4 cooperates with the tapping of the lower part 32.4 of the opening 32.

Advantageously but not obligatory, the threading of the head 41 of the screw 4 comprises a brake, such as for example a transverse pin made of synthetic material, to prevent a subsequent unscrewing of the screw 4. Once the central element 3 and the screw 4 in place in the glenoid, the subassembly formed by these two elements is locked in rotation, with respect to the glenoid, around the axes X3-X'3 and X4-X'4, thanks to the opposite direction of the threading of the external lateral surface 31 of the central element 3, with respect to the direction of the threading of the rod 44 of the screw 4. Indeed, when this subassembly tends to unscrew in the direction of the threading of the external lateral surface 31 of the central element 3, the rotation is blocked by the threading of the rod of the screw 44. On the contrary, when this subassembly tends to unscrew in the direction of the thread of the rod 44 of the screw 4, the rotation is blocked by the threading of the outer lateral surface 31 of the central element 3. or after setting up the central element 3 and the screw 4, the surgeon pierces a lateral hole in the glenoid, intended to receive the lateral stud 26 of the articular body 2.

Once the central element 3 and the screw 4 in place in the glenoid, the surgeon pushes the central pin 24 of the articular body 2 into the opening 32 of the central element 3, until the lower face 23 of the plate 21 comes to bear against the upper end 33 of the central element 3. The axes X2-X'2, X3-X'3 and X4-X'4 are then merged with the axis X1-X'1 of the glenoid implant 1.

In an advantageous alternative, the surgeon pushes the central pin 24 into the opening 32, until the lower face 23 of the plate 1 bears against the glenoid, without the lower face 23 being in contact with the end. upper 33 of the central element 3. This limits the wear of the articular body 2 against the central element 3. The upper part 24.1 of the central pin is then housed in the upper part 32.1 of the opening 32, and the intermediate part 24.2 of the central pin 24 is then housed in the threaded portion 32.2 of the opening 32. When the surgeon pushes the central pin 24 into the opening 32, the fins 25 of the central pin 24 deform in contact with the threads of the tapping of the threaded portion 32.2 of the opening 32, and the fins 25 are then retained between these threads, by cooperation of shapes and flexible deformation. The lateral stud 26 is trapped in the corresponding hole pierced in the glenoid and prevents the rotation, about the axis X1-X'1, of the articular body 2 relative to the glenoid. The fins 25 prevent the translation of the articular body 2, along the axis X1-X'1, with respect to the central element 3, when the intensity of the forces applied to the glenoid implant 1 do not exceed too much the intensity of the efforts that naturally undergoes the articulation of the shoulder. However, if the surgeon wishes to separate the articular body 2 and the central element 3, it is possible to remove the articular body 2 of the central element 3 with the aid of a suitable tool, such as a clamp. Once the glenoid implant 1 is implanted in the glenoid, its rotation around the axis X1-X'1, with respect to the glenoid, is blocked. Indeed, the lateral pin 26 blocks the rotation of the articular body 2 with respect to the glenoid, and the rotation, with respect to the glenoid, of the subassembly formed by the central element 3 and the screw 4, is blocked thanks to threads in opposite directions of the central element 3 and the rod 44 of the screw 4. The blocking of the rotation of the glenoid implant 1 relative to the glenoid is essential because it prevents the glenoid implant 1 from being unsealed under the action of mechanical stresses resulting from the support and movements of the head of the humerus against the upper face 22 of the articular body 2. The lateral pin 26, which allows the locking in rotation around the axis X1 -X'1, of the articular body 2 with respect to the glenoid is optional and may be substituted by other rotational locking means. For example, the upper end of the external lateral surface of the central stud 24 may be provided to protrude axially from the central element 3, and its cross section may be provided, for example, square or hexagonal, so as to block the rotation of the articular body 2 with respect to the glenoid, once the central pin implanted in the glenoid. In this case, the surgeon digs a single cavity in the glenoid, composed of a receiving portion of the central element, aligned with a receiving portion of the screw. This is particularly advantageous because the bone tissue is then largely preserved. Figures 5 to 8 show a glenoid implant 101, according to a second embodiment of the invention, whose elements similar to those of the first embodiment bear the same references, increased by 100. Thus, the glenoid implant 101 , of longitudinal axis X101-X'101, is composed of a joint body 102 of the "metal back" type, of a central element 103 for anchoring the articular body 102 in the glene of the scapula, and of a screw 104 for locking in rotation of the central element 103 relative to the scapula.

The articular body 102, shown in bottom view in FIG. 8, comprises a plate 121 of circular cross-section, perpendicular to a longitudinal axis X102-X'102 of the articular body 102. The plate 121 is delimited by an upper face 122 and by a lower face 123. 126, a frustoconical lateral surface of the plate 121.

The upper face for receiving an additional piece, not shown, adapted to articulate with the humerus. In the case of an inverted prosthesis, this additional piece is hemispherical, and an implant comprising a concave articular surface may be implanted in the humerus. Four housing portions 121a, 121b, 121c and 121d in the form of a sphere section are hollowed out in the plate 121 and open at the same time on the upper face 122 and on the lower face 123. Two bushes 105 have a spherical outer surface and are received in dwellings 121b and 121d. The sockets 105 are in ball joint connection with the articular body 102. The sockets 105 are each traversed by a tapped hole intended to receive a screw 106. The screws 106 are represented solely by their center line in FIG. 123 of the plate 121 is equipped with a central pin 124, of longitudinal axis X102-X'102, which comprises a cylindrical upper portion 124.1 with circular section, connected to the lower face 123, and a frustoconical lower portion 124.2, the diameter decreases away from the plate 121. The articular body 102 is traversed longitudinally by a through opening 125, centered on the axis X102-X'102, which comprises a threaded upper part 125.1, and a cylindrical section lower part 125.2 circular. The tapping of the upper portion 125.1 is provided for attachment to the articular body 102 of the additional piece intended to articulate with the head of the humerus. The articular body 102 is metallic or ceramic. For example, articular body 102 may be made from stainless steel, titanium, titanium alloy or cobalt-chromium. The central element 103, seen more particularly in FIG. 7, is generally in the form of a hollow cylinder with a circular cross section, with a longitudinal axis X103-X'103. The central element 103 is delimited by an external lateral surface 131 which carries a self-tapping thread, and is traversed longitudinally by an opening 132 which extends between an upper end 133 and a lower end 134 of the central element 103. The lower end 134 of the central element 3 is frustoconical and its diameter decreases as it approaches the lower end 134.

The opening 132 comprises a cylindrical upper portion 132.1, of circular section, a frustoconical portion 132.2, the diameter of which decreases towards the lower end 134, a hexagonal portion 132.3 whose cross section is in the shape of a hexagon, a rounded portion 132.4 dome-shaped, whose apex is facing downwards, and a bottom portion 132.5 cylindrical, circular section. The central element 103 is metallic or ceramic. For example, the central member 103 may be made from stainless steel, titanium, titanium alloy or cobalt-chromium. The screw 104, having a longitudinal axis X104-X'104, comprises a head 141 and a self-tapping threaded rod 144. A blind hole 142 with a square section, centered on the longitudinal axis X104-X'104, is formed in the head 141 of the screw 104. An external lateral surface 143 of the head 141 is in the form of a dome whose apex is turned down and whose geometry is complementary to that of the rounded portion 132.4 of the opening 132 of the central element 103.

The screw 104 is metallic or ceramic. For example, the screw 104 may be made from stainless steel, titanium, titanium alloy or cobalt-chromium. The threading of the outer lateral surface 131 of the central element 103 is on the right, as represented by the arrow F131, while the thread of the rod 144 of the screw 104 is on the left, as represented by the arrow F144.

When it is advisable to place the glenoid implant 101 in the glenoid of the scapula, the surgeon first pierces a hole in the glenoid, slightly smaller in diameter than the external diameter of the central element 103. Then, the surgeon screwing the central element 103 into the glenoid, by means of a tool, not shown, equipped with a hexagonal tip that inserts into the hexagonal portion 132.3. The self-tapping thread of the central element 103 allows it to enter the glenoid by tapping. The surgeon makes a hole in the glenoid, of a diameter slightly smaller than the diameter of the rod 144 of the screw 104, by passing a wick, not shown, through the opening 132 of the central element 103. The wick is guided by a tool, not shown, engaged in one of the parts of the opening 132. The surgeon then screws the screw 104 into the hole he has just made, using a tool, not shown, equipped with a tip with square section that it inserts into the blind hole 142 of the screw 104. At the end of the stroke, the external lateral surface of the head 141 of the screw 104 bears against the lateral surface of the portion 132.4 of the opening 132 of the central element 103.

Once the central element 103 and the screw 104 implanted in the glenoid, the subset formed by these two elements is locked in rotation, relative to the scapula, thanks to the opposite direction of the threading of the outer surface 131 of the central element 103, with respect to the thread direction of the rod 144 of the screw 104.

Once the central element 103 and the screw 104 in place in the glenoid, the surgeon drives the central pin 124 of the articular body 102 into the opening 132 of the central element 103, so that the frustoconical lower portion 124.2 of the pion central 124 is wedged in the frustoconical portion 132.2 of the opening 132. This assembly type "Morse taper" can block the translation and rotation of the articular body 102 relative to the central element 103, when the intensity of efforts applied to them does not go too far beyond that of the efforts which a joint naturally undergoes. However, if it is necessary to remove the glenoid implant 101 of the scapula, the surgeon, with the aid of appropriate tools, can unmount the articular body 102 of the central element 103.

The screws 106 are provided to more solidly secure the articular body 102 to the glenoid and thereby block the rotation of the articular body 102 relative to the glenoid. The rotation of the sockets 105 in the housings 121b and 121d makes it possible to orient the screws 106 in an appropriate manner. The articular body 102 may alternatively be attached to the central member 103 prior to insertion of the screw 104 or prior to screwing the central member 103 into the glenoid. Finally, the surgeon fixed to the articular body 102 the additional piece, intended to articulate with the head of the humerus. This additional piece is screwed into the tapping of the upper portion 125.1 of the housing 125. The additional piece comprises a frustoconical recess provided to engage on the lateral surface 126 of the plate 121. Figures 9 and 10 show a glenoid implant 201 according to a third embodiment of the invention, whose elements similar to those of the first embodiment bear the same references, increased by 200. Thus, the glenoid implant 201, of longitudinal axis X201-X'201, is composed of a joint body 202, of "metal back" type, and a central element 203 for anchoring the articular body 202 in the glenoid of the scapula. The articular body 202, of longitudinal axis X202-X'202, comprises a circular plate 221, perpendicular to the axis X202-X'202, which is delimited by an upper face 222 and by a lower face 223. 226 , a lateral surface of the plate 221. The lower face 223 is equipped with a central cylindrical pin 224 with a circular section, centered on the axis X202-X'202. The central pin 224 is hollow and defines a frustoconical housing 225, the diameter of which decreases when approaching the plate 221. The upper face 222 of the plate 221 is intended to receive an additional piece, not shown, able to articulate with the head of the humerus.

The central element 203, with a longitudinal axis X203-X'203, comprises a frustoconical intermediate portion 203.2 whose diameter decreases between an upper end 233 and a lower end 234 of the central element 203. An external lateral surface 231 of the intermediate portion 203.2 carries a self-tapping thread and is traversed transversely by holes 238. The intermediate portion 203.2 is extended downwardly by a frustoconical lower portion 203.3, whose conicity is greater than that of the intermediate portion 203.2. The intermediate portion 203.2 is extended upwards by a frustoconical upper portion 203.1, the diameter of which decreases as it approaches the upper end 233. A peripheral groove 237 is defined between the intermediate portion 203.2 and the upper portion 203.1. The central element 203 is traversed by a longitudinal opening 232, centered on the axis X203-X'203, which opens on either side of the central element 203. The opening 232 is composed of an upper part 232.1, of section hexagonal transverse section, and a cylindrical bottom portion 232.2 of circular section which connects the upper part 232.1 to the lower end 234 of the central element 203.

The holes 238 are distributed over the entire intermediate portion 203.2 and open into the lower part 232.2 of the opening 232. When it is advisable to place the glenoids implant 201 in the scapula, the surgeon will first pierce a hole in the glenoid, of diameter slightly less than the diameter of the central element. Then, the surgeon screws the central element 203 into the glenoid, by means of a tool, not shown, equipped with a hexagonal tip that it inserts into the upper part 232.1 of the opening 232. The articular body 202 is assembled to the central element 203, by engaging the central pin 224 on the upper part 203.1 of the central element 203. When the articular body 202 is assembled to the central element 203, the articular body 202 is locked in translation and in rotation with respect to the central element 203 thanks to the fixation of "cone-walrus" type between these two elements. Once the glenoid implant 201 has been placed, the bone tissue of the glenoid colonises the holes 238 of the central element 203 and the opening 232, which contributes to blocking the rotation of the central element 203 relative to the Glenene, and improves the holding of the glenoid implant 201. The rotation of the articular body 202 relative to the glenoid is blocked by means of screws and sockets not shown, similar to the screws 106 and the sockets 105 of the second embodiment. production. Figures 11 and 12 show a glenoid implant 301, according to a fourth embodiment of the invention, the elements similar to those of the third mode bear the same references, increased by 100. The glenoid implant 301, axis X301-X'301 longitudinal, is composed of an articular body 302 and a central element 303 for anchoring the articular body 302 in the glenoid of the scapula. The articular body 302, after its attachment to the glenoid, is adapted to articulate with a head, possibly prosthesis, of the humerus, not shown, of the operated patient, in order to reproduce an articular behavior as close as possible to the behavior origin of the patient's shoulder. The articular body 302, of longitudinal axis X302-X'302, comprises a plate 321, generally perpendicular to the axis X302-X'302, delimited by an upper face 322 and by a lower face 323. The upper face 322 constitutes an articular surface for the articulation of the scapula with the head of the humerus. The lower face 323 of the plate 321 is provided with a central pin 324, centered on the axis X302-X'302, whose external lateral surface is hexagonal. The central pin 324 is hollow and defines a frustoconical housing 325, whose diameter increases away from the plate 321.

As clearly visible in FIGS. 11 and 12, the plate 321 has an elongated shape and extends along a longitudinal axis Y321-Y'321, perpendicular to the axis X302-X'302. The central pin 324 is offset longitudinally, along the axis Y321-Y'321 relative to the center C21 of the plate 321. The articular body 302 is made from one or two biocompatible synthetic materials and adapted to a partial or total articulation. such as polyethylene, PEEK or polyurethane. The central element 303 is substantially identical to the central element 203 of the glenoid implant according to the third embodiment. Thus, the central element 303 comprises a frustoconical intermediate portion 303.2 whose diameter decreases between the upper end 333 and the lower end 334 of the central element 303. An external lateral surface 331 of the intermediate portion 303.2 carries a self-threading and is traversed transversely by holes 338 which are located at the bottom of the intermediate portion 303.2. The intermediate portion 303.2 is extended downwards by a frustoconical lower portion 303.3, whose conicity is greater than that of the intermediate portion 303.2. The intermediate portion 303.2 is extended upwards by a frustoconical upper portion 303.1, the large diameter of which is on the side of the intermediate portion 303.2. A peripheral groove 337 is defined between the intermediate portion 303.2 and the upper portion 303.1. The central element 303 is traversed by a longitudinal opening 332, which opens on either side of the central element 303 and which communicates with the holes 338. The opening 332 is composed of an upper portion 332.1 of cross section hexagonal, which opens on the upper end 333 of the central element, and a cylindrical bottom portion 332.2 circular section which connects the upper part 332.1 to the lower end 334 of the central element 303.

The implantation of the glenoid implant 301 is similar to that of the glenoid implant 201 according to the third embodiment. The hexagonal shape of the central pin 324 of the articular body 302 makes it possible to block the rotation of the articular body 302 with respect to the glenoid. Once the glenoid implant 301 has been placed, the bone tissue of the glenoid can recolonize the holes 338 and the opening 332 of the central element 303, which contributes to blocking the rotation of the central element 303 with respect to the glenoid and improves the strength and the life of the glenoid implant 301. The rotational locking of the central element 303 relative to the glenoid is performed partially or exclusively through the articular body 302. Indeed , thanks to its hexagonal section of the central pin 324, the rotation of the articular body 302 relative to the glenoid is blocked. Given that the articular body 302 and the central element 303 are both locked in rotation relative to the glenoid, it is not essential to provide means for blocking the rotation of the articular body 302 with respect to the central element 303. However, it is conceivable to effect a locking, for example of the tenon and mortise type, of the rotation of the articular body 302 with respect to the central element 303. FIGS. 13 and 14 represent the articular body 202 and the central element 203 of the glenoid implant 201 of the third embodiment. The articular body 302 of the fourth embodiment is superimposed with the articular body 202, and is shown in a position in which it is assembled with the central element 203. The lateral offset of the central pin 324 with respect to the longitudinal axis Y 321-Y'321 of the plate 321 is clearly visible in FIGS. 11 and 12, where a long portion 321.1 of the plate 321 situated on one side of a plane P perpendicular to the axis X302-X'302 protrudes laterally. 202. A short portion 321.2 of the plate 321 is situated on the other side of the plane P. When the surgeon implants the glenoid implant 301 in the scapula, he positions the articular body 301 by orienting the central pin 324 towards the at the bottom, so that when the operated patient raises the arm, the head of the humerus tends to tilt the long portion 321.1 of the plate 321 to the shoulder blade, as represented by the arrow F. The lower face 323 of the long section 321.1 es t in direct contact with the glenoid, since the pin 324 is offset laterally, which advantageously allows the glenoid to directly cash the compression force resulting from the tilting of the long portion 321.1. FIGS. 15 and 16 show a glenoids implant 401, according to a fifth embodiment of the invention, whose elements similar to those of the fourth embodiment bear the same references, increased by 100. The gleno implant idien 401 is composed of an articular body 402, strictly identical to the articular body 302 of the fourth embodiment, and a central element 403, of the "press fit" type, for anchoring the articular body 402 in the glenoid scapula.

Thus, the articular body 402, of longitudinal axis X402-X'402, comprises a plate 421, whose upper face 422 constitutes an articular surface for the articulation of the scapula with the head of the humerus. A lower face 423 of the plate 421 is provided with a central pin 424 of hexagonal cross-section. The central pin 424 is hollow and defines a frustoconical housing 425 whose diameter decreases as it approaches the plate 421. The articular body 402 is made from one or two biocompatible synthetic materials, for example polyethylene, PEEK or polyurethane. The central element 403, with a longitudinal axis X403-X'403, comprises a lower part 403.2 in the form of a hexagonal prism. 433 is an upper end of the central element 403, and 434 a lower end of the central element 403. The lateral edges of the central element are beveled progressively towards the lower end 434. The lower part 403.2 is transversely through holes 438. The lower portion 403.2 is extended upwardly by a frustoconical upper portion 403.1, whose diameter decreases away from the upper portion 403.1. A peripheral groove 437 is defined between the upper portion 403.1 and the lower portion 403.2. The central member 403 is made from a biocompatible metal material or ceramic, such as stainless steel, titanium, a titanium alloy or a carbon alloy.

When it is advisable to place the glenoid implant 401 in the glenoid of the scapula, the surgeon first pierces a hole in the glenoid slightly smaller than that of the central element 403. Then, the surgeon impact the central member 403 to enter the hole. The penetration of the central element 403 into the glenoid is facilitated thanks to the beveled lateral edges. The rotation of the central element 403 with respect to the glenoid is blocked thanks to the hexagonal shape of the cross section of the central element 403. The bone regrowth in the holes 438 also contributes to blocking the rotation of the central element 403. compared to the glenoid. Then, the surgeon fits the central pin 424 of the articular body 402 on the upper part 403.1 of the central element 403. When the articular body 402 is assembled to the central element 403, the articular body 402 is locked in translation and in rotation relative to the central element 403 thanks to the fixation type "cone-walrus" between these two elements. The X402-X'402 and X403-X'403 axes are then aligned and coincide with the longitudinal axis X401-X'401 of the glenoid implant 401.

The rotational locking of the articular body 402 with respect to the glenoid is provided by the hexagonal section of the central pin 424, and by the friction between the upper part 403.1 of the central element 403 and the housing 425 of the central pin 424. Thus, the glenoid implant 401 is locked in rotation, around the axis X401-X'401, relative to the scapula.

FIGS. 17 and 18 show a glenoids implant 501, according to a sixth embodiment of the invention, whose elements similar to those of the fourth embodiment bear the same references, increased by 200. The gleno implant idien 501 is composed of an articular body 502, identical to the articular body 302 of the fourth embodiment, and a central element 403 for anchoring the articular body 402 in the glenoid of the scapula. The articular body 502 comprises a plate 521 delimited by a concave upper face 522, which constitutes an articular surface for the articulation of the scapula with the head of the humerus, and by a lower surface 523, equipped with a central pin. 524 cylindrical with circular section. The central pin 524 is hollow and defines a frustoconical housing 525, whose diameter increases away from the plate 521. The lower face 523 is also equipped with a lateral stud 526, parallel to the central pin 524, which comprises an upper part 526.1 cylindrical circular section, of diameter smaller than the diameter of the central pin 524, which is connected to the lower face 523 of the plate 521. The lateral pin 526 also comprises a frustoconical lower portion 526.2, connected to the upper portion 526.1, whose diameter is increased away from the plate 521. The inner side surface of the central pin 524 is provided with a peripheral fin 527. The central element 503 comprises a frustoconical intermediate portion 503.2 whose diameter decreases between an upper end 533 and a lower end 534 of the central element 503 and which communicates with the holes 538. An external lateral surface 531 of the intermediate part Ediary 503.2 carries a self-tapping thread and is traversed transversely by holes 538 which are located at the bottom of the intermediate portion 503.2. The intermediate portion 503.2 is extended downwards by a frustoconical lower portion 503.3, whose conicity is greater than that of the intermediate portion 503.2. The intermediate portion 503.2 is extended upwards by a frustoconical upper portion 503.1, the large diameter of which is on the side of the intermediate portion 503.2. A peripheral groove 537 is hollowed out at the junction between the upper part 503.1 and the intermediate part 503.2. The central element 503 is traversed by a longitudinal opening 532, which opens on either side of the central element 503 and which communicates with the holes 538. The opening 532 is composed of an upper part 532.1 of cross section hexagonal, which opens on the upper end 533 of the central element, and a cylindrical lower section 532.2 circular section which connects the upper portion 532.1 to the lower end 534 of the central element 503.

When it is advisable to implant the gléno'idien implant 501 in the glenoid of a patient, the surgeon preliminarily pierces a hole of dimensions slightly smaller than the dimensions of the central element 503. The surgeon also pierces a receiving hole of the patient. lateral pad 526. Then, the surgeon screws the central element 503 into the hole, by means of a tool equipped with a hexagonal tip that it inserts in the upper part 532.1 of the opening 532 of the element Central 503. Then, the surgeon closes the articular body 502 on the upper part 503.1 of the central element. The peripheral fin 527 is then positioned in the groove 537 of the central element 503, which makes it possible to block the translation of the articular body 502 with respect to the central element. The lateral block 526 makes it possible to block the rotation of the articular body 502 with respect to the glenoid. Once the glenoid implant 501 has been placed, the bone tissue of the glenoid can recolonize the holes 538 and the opening 532 of the central element 503, which contributes to blocking the rotation of the central element 503 with respect to the glenoid and improves the holding of the glenoid implant 501.

It will be noted that the central elements of the glenoidal implants according to the third to sixth embodiments of the invention are designed to be able to receive indifferently a metal or ceramic articular body and a synthetic articular body. Indeed, the central element 203 of the glenoid implant 201 allows the attachment of a metal or ceramic joint body, by means of the upper portion 203.1 which constitutes a fitting cone. In addition, the groove 237 of the central element 203 closes a synthetic articular body provided with a peripheral fin similar to the fin 527 of the articular body 502. Similarly, the central elements 303, 403 and 503 are provided, the same effect, a frustoconical portion 303.1, 403.1, 503.1, to be fitted in a frustoconical housing 325, 425, 525 defined by a metal or ceramic joint body, and a groove 337, 437, 537 clipping a synthetic articular body. In a variant of the first embodiment, the tapping of the threaded portion 32.2 is replaced by grooves distributed along the axis X3-X'3. On the other hand, the number of fins 25 can vary. In a variant of the first embodiment, the articular body 2 is made of a hard metal or ceramic material, such as pyrocarbon. This material is not intended to deform, the attachment between the articular body 2 and the central element 3 is, for example, Morse taper type. This attachment replaces the fins 25. It will be noted that the PEEK has a relatively high rigidity for a polymer. Thus, it is conceivable to use a Morse taper type fitting to fix a PEEK element. Similarly, in the fourth and fifth embodiments, it is conceivable to manufacture the articular bodies 302 and 402 in a hard metal or ceramic material, such as pyrocarbon. In a further variant of the first embodiment, the upper part 32.1 of the opening 32 of the central element 3 and the upper part 24.1 are frustoconical instead of being cylindrical. In another variant not shown of the first embodiment, the thread of the outer lateral surface 31 of the central element 3 is on the left, while the thread of the rod 44 of the screw 4 is on the right. In this case, the thread of the head 41 of the screw 4 is on the right and the thread of the lower part 32.4 of the opening 32 is also on the right.

In another non-illustrated variant of the second embodiment, the threading of the outer lateral surface 131 of the central element 103 is on the left, while the threading of the rod 144 of the screw 104 is on the right. As a variant, in the second embodiment, the portion 132.1 of the opening 132 of the central element 103 is frustoconical and the portion 132.2 is cylindrical. In a variant of the first and second embodiments, the screws 4 and 104 are made of polymer, for example made of PEEK. In a variant of the first, second and fifth embodiments, the central elements 3, 103 and 403 are made of polymer, for example made of PEEK.

In a variant of the second embodiment, the lower portion 124.2 of the central pin 124 is cylindrical with a circular section. In this case, the portion 132.2 is also cylindrical with a circular section and is adapted to receive the lower portion 124.2 of the central pin 124, so that the attachment of the articular body 102 is achieved by forcing the central pin 124 into the element central 103.

In a variant of the fourth and fifth embodiments, the cross section of the central pin is in the form of a polygon which has a number of sides different from four. For example, the central counter may be triangular or octagonal. In a variant not shown, a central element defines a housing for receiving a central pin of an articular body. For example, to be able to receive a synthetic articular body, the housing of a central element may comprise an internal thread, similar to the threading of the threaded portion 32.2 of the central element 32, in which are clipped wings provided along of a central pawn of an articular body. In addition, to be able to receive a metal or ceramic articular body, the central element may comprise a frustoconical housing for receiving a frustoconical central pin of an articular body. Alternatively, in the first embodiment, the hexagonal portion 32.3 of the central member 3 and the blind hole 42 of the head of the screw 4 may be square section, cross-shaped, a Torx fingerprint (registered trademark) , or any other geometry allowing a tool grip. The same applies to the second embodiment with regard to the blind hole 142 of the screw 104 and for the hexagonal portion 132.3 of the central element 103. The tip of the tools used are obviously adapted to the fingerprints of the elements to screw. In a variant of the second and third embodiments, the articular bodies 102 and 202 are equipped with two additional sockets 105 housed in the housing 121a and 121c or 221a and 221c.

In addition, the various embodiments and variants described above can be, partially or totally, combined with each other to give rise to other embodiments.

Claims (1)

1. A glenoid implant (1; 101; 201; 301; 401; 501) for a shoulder prosthesis intended to be implanted in the glenoid of a scapula, comprising an articular body (2; 102; 202; 302; 402; 502), for articulation with the humerus, and a central element (3; 103; 203; 303; 403; 503) for fixing the articular body (2; 102; 202; 302; 402; glenoid, the articular body (2; 102; 202; 302; 402; 502) comprising a plate (21; 121; 221; 321; 421; 521), one face (23; 123; 223; 323; 423; 523); , intended to be facing the glenoid, is provided with a central pin (24; 124; 224; 324; 424; 524) for joining the articular body (2; 102; 202; 302; 402; 502) with central element (3; 103; 203; 303; 403; 503), the central element (3; 103; 203; 303; 403; 503) being provided with connecting means (32.1, 32.2; 132.1; 132.2; 203.1, 237, 303.1, 337, 403.1, 437, 503.1, 537) with the central pin (24; 124; 224; 324; 424; 524), the glenoid implant (1; 101; 201; 301; 401; 501) being characterized by comprising means (26,31,44; 106,131,104; 238; 324,338; 424 403.2, 438, 526, 538) for locking the rotation of the central member (3; 103; 203; 303; 403; 503) and / or the joint body (2; 102; 202; 302; 402; 502 ), with respect to the glenoid. 2. Glnoidal implant (1; 101) according to claim 1, characterized in that the means for locking the rotation comprise a screw (4; 104), in that the central element (3; 103) is traversed longitudinally. by an opening (32; 132) for the passage of the screw (4; 104), and in that the rod (44; 144) of the screw (4; 104) is threaded in a direction opposite to a thread carried by the external lateral surface (31; 131) of the central element (3; 103). 3. The glenoid implant (1) according to claim 2, characterized in that the head (41) of the screw (4) is threaded in the same direction as the rod (44) of the screw (4). 4. Glenoid implant (1) according to claim 3, characterized in that the pitch of the thread of the head (41) of the screw (4) is equal to the pitch of the thread of the rod (44) of the screw (4). ). 23 5. Glnoidal implant (301; 401) according to one of the preceding claims, characterized in that the rotation locking means comprise an outer lateral surface of the central pin (324; 424) of polygonal cross section. 6. Glnoidal implant (201; 301; 401; 501) according to one of the preceding claims, characterized in that the assembly means (203.1, 237; 303.1, 337; 403.1, 437; 503.1, 537) are adapted to cooperate indifferently with a joint body (202) metal or ceramic and with a joint body (302; 402; 502) synthetic. 7. The glenoid implant (201; 301; 401; 401; 501) according to claim 6, characterized in that the assembly means comprise a frustoconical portion (203.1; 303.1; 403.1; 503.1) or a frustoconical housing (132.2). , adapted to cooperate by fitting, in particular of Morse taper type, with, respectively, a frustoconical housing (225; 325; 425; 525) or a frustoconical portion (124.2) of the central pin (224; 324; 424; 524). 8. Glnoidal implant (201; 301; 401; 501) according to one of claims 6 and 7, characterized in that the assembly means comprise a peripheral fin (527) or a peripheral groove (32.2) adapted for cooperating by flexible deformation and complementarity of shapes with, respectively, a groove (537) or a fin (25) of the central pin (224; 324; 424; 524). 9. Glenoid implant (1; 301; 401; 501) according to one of the preceding claims, characterized in that the plate (21; 321; 421; 521) is of elongate shape and in that the pion central (24; 324; 424; 524) is offset along a longitudinal axis (Y321-Y'321) of the plate (21; 321; 421; 521) relative to the center (C21) of the plate (21; 321; 421; 521). 10. Surgical kit, characterized in that it comprises at least one central element (202; 203; 303; 403; 503) belonging to a glenoid implant (201; 301; 401; 501) according to claim 6, at least a metal or ceramic articular body (202) belonging to a glenoid implant (201; 301; 401; 501) according to claim 7 and at least one synthetic articular body (302; 402; 502) belonging to a glenoid implant (201; 301; 401; 501) according to claim 8.